<\body> styles> The user may select a major style from the menu. The major style usually reflects the kind of document you want to produce (like a letter, an article or a book) or a particular layout policy (like publishing an article in a given journal). In addition to a major style, the user may select one or more additional packages from . Such packages may customize the major style, provide additional markup, or a combination of both. In this chapter, we will survey the standard document styles and packages provided by . Most style files and packages have an abstract interface, the (data domain definition), which specifies which macros are exported by the style or package, and how to use them. Distinct styles or packages (like and ) may share the same abstract interface, but differ in the way macros are rendered. For this reason, we will mainly be concerned with the description of the standard s, except when we focus on the rendering. Users may customize standard styles by defining new ones which match the same abstract interface (see the chapter on style files|../../devel/style/style.en.tm>). <\traverse> <\initial> <\collection>